a = 1
b = 2

# 定义变量
# c = a
# a = b
# b = c
# print(a,b)

# 利用算数运算符
# a = a + b
# b = a - b
# a = a - b
# print(a,b)

# 利用元组
a, b = b, a
print(a,b)
